Therapeutic inhibition of Fas-mediated retinal cell death and inflammation in dry AMD

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PROJECT SUMMARY / ABSTRACT Age-related macular degeneration (AMD) is the leading, and due to the aging baby boomers, a growing cause of irreversible vision loss in the United States, and is strongly associated with exposure to cigarette smoke (CS) and high fat diets (HFD). While effective treatment is available for neovascular AMD, the AREDS II antioxidant vitamins are the only proven treatment for intermediate dry AMD. Unfortunately, AREDSII is not effective for early or late dry disease, and in intermediate AMD, it merely slows the progression to advanced disease. Treatments that target dry AMD will have a huge impact on the afflicted individual and save billions of health care dollars per year. Impairment of the oxidative stress response, autophagy, mitochondrial function, and the unfolded protein response, as well as dysregulated innate immunity have been implicated in AMD, and thus, have been investigated as treatment targets. Ultimately, these abnormalities cause death of retinal pigment epithelial (RPE) cells and photoreceptors (PR), leading to permanent vision loss. Fas-mediated cell death is the major mechanism of outer retinal cell loss in many retinal diseases including AMD. With no therapy to prevent Fas-mediated outer retinal cell death in AMD, a logical treatment strategy is to prevent Fas- mediated signaling, irrespective of the upstream impairment. ONL Therapeutics, an ophthalmic biotechnology company developing innovative therapies that prevent retinal cell death to improve visual outcomes for patients, has demonstrated the effectiveness of Fas inhibition in preventing retinal cell death in an acute model of AMD. Additionally, a gene therapy that inhibits Fas signaling has been developed and tested in acute and chronic models of glaucoma, wherein the vector provided significant inner retinal neuroprotection. Due to the role of Fas in AMD and the effect of Fas inhibition in protecting the retina following ocular stress, this proposal will examine the effect of the Fas inhibitors in acute and chronic models of atrophic AMD. Phase I of this Fast- track STTR proposal will i) determine the feasibility of using Fas inhibition to protect against acute CS-induced retinal damage, and ii) demonstrate that the duration of inhibition is clinically meaningful. Phase II will test the ocular safety and effectiveness of repeated intravitreal injections of our peptide Fas inhibitor. In addition, we will test the effectiveness of repeated intravitreal injections of the peptide Fas inhibitor as well as a single intravitreal injection of a Fas inhibitor vector in a novel, peer-reviewed chronic model of atrophic AMD in which apoB100 mice exposed to CS and HFD develop a geographic atrophy phenotype that closely resembles human disease. This proposal combines the expertise of ONL and the Wilmer Eye Institute to test these Fas inhibitors in models of atrophic AMD. Successful execution of the project will support the continued pre-clinical development of the Fas inhibitors for dry AMD and help attract additional investor interest in the company.